Remoistenable adhesive sheet



Sept 6, 1966 R. s. lvEs 3,271,28

REMOISTENABLE ADHESIVE SHEET Filed oct. 14,1963

INVENTOR.

te States Patent 3,271,228 REMOISTENABLE ADHESIVE SHEET Robert S. Ives,Lexington, Mass., assgnor to Gurdon S. Worcester, Gloucester, Mass.Filed Oct. 14, 1963, Ser. No. 315,832 4 Claims. (Cl. 161-151) Thisinvention relates to adhesive tapes, labels and the like sheets andparticularly to a nonblocking flexible sheet whose adhesive may bereactivated as contrasted with sheets whose adhesive is pressuresensitive.

For example, remoistenable labels and tapes whose adhesive is watersoluble, animal glue, although among the oldest adhesive sheets, yarestill among the most widely used. Despite its long history, however,remoistenable adhesive has an inherent disadvantage. Without an addedplasticizer, the adhesive and the supporting base on which it is coated,are sti and crackly and therefore deteriorate when bent or warped in useor when stored in a roll and also must go through a breaking operationto prevent curling. On the other hand, when a plasticizer is added tothe adhesive to make it more pliable, superimposed sheets or turns,Will, after a short time, block or stick to each other. Flexibility andtackiness are concomitant; if the desirable fiexibility is present, sois the unwanted tendency to block. Blocking may be avoided by coveringthe adhesive with a waxy release sheet but such is not the purpose ofthe present invention.

The object of this invention is to provide an adhesive sheet of the typewhich is both liexible and nonblocking, but which is easily reactivatedas by moistening for use.

According to the invention an adhesive sheet comprises a liexible baseweb, a layer of reactivatable adhesive on the base, said adhesive beingin tacky, flexible state, and a thin, flexible fibrous layer at leastpartially covering said adhesive layer, the inner side of said fibrouslayer being permanently imbedded in said adhesive layer, said adhesivelayer extending only partially toward the outer side of said fibrouslayer, said adhesive layer being readily reactivated through saidfibrous layer and said fibrous layer being readily penetrated byreactivated adhesive from the inside to the outside of said fibrouslayer, `whereby said -brous layer prevents blocking of a plurality ofsaid sheets when stored in superposition, while permitting said adhesivelayer to be easily reactivated for adhering a sheet to a surface.

For the purpose of illustration a typical embodiment of the invention isshown in the accompanying drawing in which FIG. l is a plan view, partlybroken away, of an adhesive sheet according to the invention;

FIG. 2 is an enlarged section on line 2 2 of FIG. l;

FIG. 3 is a side elevation of a roll of adhesive tape embodying avariation of the invention;

FIG. 4 is an enlarged section on line 4-4 of FIG. 3;

FIG. 5 is an isometric view of an envelope made with adhesive sheetaccording to the invention; and

FIG. 6 is an enlarged section on line 6 6 of FIG. 5.

As shown in FIGS. 1 and 2 an adhesive sheet comprises a supporting baseweb 1 of heavy, calendered kraft paper to which a layer 2 of hide glueformulation is adhered. Adhered to the glue layer is a thin, fibroussheet 3 such as tissue paper partly imbedded in the glue.

The fibrous layer is preferably the thinnest, most open sheet such assingle ply facial or toilet tissue but may 'be a flocked or nonwovenfabric layer. The fibrous layer is easily wettable and penetrable bywater or an aqueous solution.

3,271,228 Patented Sept. 6, 1966 An excess of the glue heated to F. isapplied to the base sheet and spread to a thickness equivalent to thedistribution by a standard No. 32 or 40 paper coating rod. The basesheet and fibrous layer are then forced together so that the libres atthe inner side of the fibrous layer are imbedded in the blue layer butso that the glue does not extend to the outer surface of the fibrouslayer. The adhesive sheet is then dried.

When dried the adhesive layer is maintained soft and flexible by theglycerine and sorbitol as plasticizers. As previously stated,flexibility is accompanied by tackiness. However, the thin layer oftissue guards the tacky glue layer so that the sheeting, which isflexible as a whole, may be handled, stacked or rolled dry withoutsticking o1' blocking.

For use the fibrous layer is moistened in the conventional way, themoisture readily penetrating the fibrous layer so `as to dissolve theblue which then migrates back through the fibrous layer over theexterior of the fibrous layer. The fibers of this layer remainsubstantially embedded in the glue layer, but because of their thin opencharacter do not interfere appreciably with the adhesion of the glue onthe surface to which the sheet is applied. The usual sight pressureapplied aids the dissolved glue in migrating through the fibrous layer.

The adhesive sheet described thus has a quality of softness andflexibility commensurate with the supporting base, will not block duringlong storage under humid conditions, and is easily remoistened for usein a conventional way.

The adhesive sheet may be wound in a roll as shown in FIGS. 3 and 4without blocking of adjacent base webs 1 and fibrous layers 3. Migrationcan be aided by impregnating the fibrous layer, preferably beforeadhering it to the glue layer, with a wetting agent 5 such as Rohm andHaas Triton X-lOO, an octyl phenoxy polyethoxy ethanol with an averagepolyoxyethylene chain length of 9 to 10.

Adhesive sheet according to the invention may be used to particularadvantage in making an envelope such as is illustrated in FIG. 5. Asillustrated the envelope 6 comprises two plies 7 of adhesive sheetjoined by a glue bond 8 at three sides. Such an envelope made with plieshaving an integral glue layer is temporarily waterproof when immersed inan aqueous solution, for example, when used as a mitten to protect theusers hand while cleaning a household bowl. After use the mitten isdischarged in the bowl `and softens and disintegrates. My invention isnot the mitten as so far described, but rather is the following mittenstructure.

As shown in FIG. 6 the individual plies 7 of the envelope are formed ofa sheet 9 of rough fibrous paper such as paper hand towels bonded to atissue sheet 11 by a slowly water soluble, and temporarily waterproofglue layer 11. The sheet is formed as previously described withreference to FIGS. l to 4. The bond 8 is formed at the edges of theenvelope by softening the gummed layer and pressing the edges together.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims. Forexample, various quick setting, heat-activatable or water solubleadhesive materials, such as polyvinyl alcohol, may be used between thebase web and fibrous layer.

I claim:

1. A remoistenable adhesive sheet comprising a flexible base web, alayer of water soluble adhesive on the base, said-adhesive being intacky, flexible state, and a thin, .ilexible brous layer at leastpartially covering said adhesive layer, the inner side of said fibrouslayer being imbedded in said adhesive layer, said adhesive layerextending only partially toward the outer side of said iibrous layer,and said brous layer being readily penetrable by softened adhesive fromthe inside to the outside of said -brous layer, whereby said fibrouslayer prevents blocking of a plurality of said sheets when stored insuperposition, while permitting said adhesive layer to be easilyactivated for adhering a sheet to a surface.

2. A remoistenable adhesive sheet according to claim 1 wherein saidfibrous layer contains a wetting agent.

3. A remoistenable adhesive sheet according to claim 1 wherein theaforesaid base web is relatively water impenetrable.

I4. A remoistenable adhesive sheet comprising a flexible base web, alayer of water soluble adhesive on the base, said adhesive being intacky, flexible state, and a thin,

flexible brous layer at least partially covering said adhesive layer,the inner side of said brous layer being permanently imbedded in saidadhesive layer, said adhesive layer extending only partially toward theouter side of said fibrous layer, and said fibrous layer being readilypenetrable by Water from its outer side `and by moistened adhesive fromthe inside to the outside of said brous layer, whereby said iibrouslayer prevents blocking of a plurality of said sheets when stored insuperposition, while permitting said adhesive layer to be easilymoistened for adhering a sheet to a surface.

References Cited by the Examiner UNITED STATES PATENTS 709,326 9/1902Howard 16l-229 X 1,101,029 `6/1914 yMagnaseo 161-229 2,353,762 7/1944Robinson et al. 161--229 X 2,364,001 ll/1944 Schieman 161-151 2,737,1793/1956 Dahle 161--159 X EARL M. BERGERT, Primary Examiner.

ALEXANDER WYMAN, Examiner.

M. SUSSMAN, Assistant Examiner.

1. A REMOISTENABLE ADHESIVE SHEET COMPRISING A FLEXIBLE BASE WEB, ALAYER OF WATER SOLUBLE ADHESIVE ON THE BASE, SAID ADHESIVE BEING INTACKY, FLEXIBLE STATE, AND A THIN, FLEXIBLE FIBROUS LAYER AT LEASTPARTIALLY COVERING SAID ADHESIVE LAYER, THE INNER SIDE OF SAID FIBROUSLAYER BENG IMBEDDED IN SAID ADHESIVE LAYER, SAID ADHESIVE LAYEREXTENDING ONLY PARTIALLY TOWARD THE OUTER SIDE OF SAID FIBROUS LAYER,AND SAID FIBROUS LAYER BEING READILY PENETRABLE BY SOFTENED ADHESIVEFROM THE INSIDE TO THE OUTSIDE OF SAID FIBROUS LAYER, WHEREBY SAIDFIBROUS LAYER PREVENTS BLOCKING OF A PLURALITY OF SAID SHEETS WHENSTORED IN SUPERPOSITION, WHILE PERMITTING SAID ADHESIVE LAYER TO BEEASILY ACTIVATED FOR ADHERING A SHEET TO A SURFACE.